Step 1: Does fdisk see the disk: yes
root@debian6~# fdisk -l /dev/sdb Disk /dev/sdb: 1000.2 GB, 1000204886016 bytes 255 heads, 63 sectors/track, 121601 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00060f19 Device Boot Start End Blocks Id System /dev/sdb1 1 254 2040254+ 83 Linux /dev/sdb2 255 121602 974722329 83 Linux
Step 2: Gently look with fsck, yes it is part of mdadm
root@debian6~# fsck -n /dev/sdb2 fsck from util-linux-ng 2.17.2 fsck: fsck.linux_raid_member: not found fsck: Error 2 while executing fsck.linux_raid_member for /dev/sdb2
Step 3: Let's see what mdadm says
root@debian6~# mdadm --examine /dev/sdb2 /dev/sdb2: Magic : a92b4efc Version : 1.0 Feature Map : 0x0 Array UUID : e8221214:354aaaf1:e9e15d78:075bfc18 Name : storage:1 Creation Time : Thu May 6 20:00:16 2010 Raid Level : raid1 Raid Devices : 2 Avail Dev Size : 1949444384 (929.57 GiB 998.12 GB) Array Size : 1949444384 (929.57 GiB 998.12 GB) Super Offset : 1949444640 sectors State : clean Device UUID : 0c265a25:cc3f2ddd:ae7a1511:f447c74e Update Time : Tue May 1 23:09:11 2012 Checksum : 498b9bd4 - correct Events : 33039098 Device Role : Active device 0 Array State : A. ('A' == active, '.' == missing)
Step 4: Let's fix the md device
root@debian6~# mdadm --assemble --scan mdadm: /dev/md/storage:1 has been started with 1 drive (out of 2). mdadm: /dev/md/0_0 has been started with 1 drive (out of 2). root@debian6~# cat /proc/mdstat Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] md126 : active (auto-read-only) raid1 sdb1[0] 2040128 blocks [2/1] [U_] md127 : active (auto-read-only) raid1 sdb2[0] 974722192 blocks super 1.0 [2/1] [U_] unused devices:
root@debian6~# fdisk -l .... Disk /dev/md127: 998.1 GB, 998115524608 bytes 2 heads, 4 sectors/track, 243680548 cylinders Units = cylinders of 8 * 512 = 4096 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Disk /dev/md127 doesn't contain a valid partition table
Step 5: Gently look with mount and lvs/pvs
root@debian6~# mount /dev/md127 /mnt mount: unknown filesystem type 'LVM2_member' root@debian6~# lvs No volume groups found root@debian6~# pvs
Step 6: Fix the lvm2 device
root@debian6~# vgscan Reading all physical volumes. This may take a while... Found volume group "md1_vg" using metadata type lvm2 root@debian6~# vgs VG #PV #LV #SN Attr VSize VFree md1_vg 1 1 0 wz--n- 929.57g 0 root@debian6~# pvs PV VG Fmt Attr PSize PFree /dev/md127 md1_vg lvm2 a- 929.57g 0 root@debian6~# lvs LV VG Attr LSize Origin Snap% Move Log Copy% Convert md1vol1 md1_vg -wi--- 929.57g
Step 7: The lvm2 device is not activated, yet
root@debian6~# lvdisplay --- Logical volume --- LV Name /dev/md1_vg/md1vol1 VG Name md1_vg LV UUID qSpslc-nO70-8jjX-5lBl-ge20-fFdR-dSEnWk LV Write Access read/write LV Status NOT available LV Size 929.57 GiB Current LE 475938 Segments 1 Allocation inherit Read ahead sectors auto
Step 8: Activate lvm2 device and mount
root@debian6~# vgchange -a y 1 logical volume(s) in volume group "md1_vg" now active root@debian6~# mount /dev/md1_vg/md1vol1 /mnt root@debian6~# mount | grep mnt /dev/mapper/md1_vg-md1vol1 on /mnt type xfs (rw)
